The present invention relates to a thermal analysis system such as a differential scanning calorimeter and a method of drying the same.
Conventionally, with a thermal analysis system, such as a differential scanning calorimeter, having a furnace body therein, an analysis has been performed by: loading a sample (a specimen) in the furnace body; using a heating device and a cooling device to raise and decrease the temperature of the sample to change the sample in temperature; and measuring absorption and radiation of heat by the sample in the form of an amount of heat. During such measurements, the temperature of the furnace body is lowered to e.g. a temperature of −70 to −150° C. constantly or temporarily. That is to say, the furnace body portion and its surroundings and the like remain cooled successively, and stay in the situations easy to cause condensation. Particularly when a sample is loaded into and unloaded from the thermal analysis system, opening an opening-and-closing cover of the thermal analysis system causes the outside air to flow into the furnace body and the inside of the case, which can cause condensation on the furnace body portion and its surroundings, and further on a temperature sensor such as a thermocouple and others, leading to adhesion of water droplets and frost thereon. When measurements are performed under the situation where the frost is thus formed, fluctuations arise in the measured temperatures to generate noises in data to be measured. This has been a cause of the impossibility of acquisition of exact measurement values. Hence, a method including uninterruptedly supplying a predetermined amount of dry gas to the thermal analysis system thereby to keep the inside of the analysis system in a dried state, and manually supplying a large amount of additional dry gas on an as-needed basis has been practiced.
Further, a method of performing automatic supply of dry gas instead of manual supply like this thereby to suppress the occurrence of condensation has been disclosed in e.g. JP-A-10-104182.
In Patent Document 1, an open-and-close sensing switch for sensing open and close states of an opening-and-closing cover provided on an outer case making an outside housing of the thermal analysis system is provided, and the supply of dry gas is controlled by ON/OFF signals from the open-and-close sensing switch. In other words, as a large amount of dry gas is supplied to the surroundings of the furnace body inside the thermal analysis system when the opening-and-closing cover is opened for loading and unloading a sample, intrusion of the outside air through the opening-and-closing cover can be cut thereby to prevent condensation and frost from forming around the furnace body.
However, as for the thermal analysis system used in JP-A-10-104182, it is expected that the humidity inside the thermal analysis system is equivalent to that of the outside air at the time when the power source is activated, i.e. before the cooling device is actuated. In that situation, actuating the cooling device will cause generation of condensation and frost and the like in the thermal analysis system owing to the moisture remaining in the analysis system. The thermal analysis system has the disadvantage that the moisture, particularly the moisture adhering to a cooling module and the like cannot be removed easily even by supplying dry gas or heating surroundings of a specimen thereafter. Therefore, the moisture which has adhered to the inside of the analysis system at the time of measurement cannot be removed sufficiently only by automatically supplying an additional dry gas at the time of opening and closing the opening-and-closing cover as described in JP-A-10-104182. This moisture causes the temperature to fluctuate and generates noises in measurement data.
In addition, a measure including manually supplying an additional dry gas thereby to dry the inside of the analysis system, and heating a heater block around a specimen thereby to accelerate the drying before the cooling device is actuated is taken separately. However, there is the problem that in the case where the drying is performed through both drying by gas and heating of the heater block before actuation of the cooling device, excessively raising the drying temperature damages the cooling module (especially, a leading end of the cooling rod) inserted in and connected with the thermal analysis system when the cooling device is e.g. an electric cooling device. Since the preferable drying time and the drying temperature vary depending on a cooling method including the type of a cooling device and its connection mode as stated above, their management has been a difficult and troublesome work.
The invention was made in consideration of the foregoing problems. Therefore, it is an object of the invention to provide a thermal analysis system and its drying method, by which working efforts by hand can be reduced by adequately selecting a dry condition in accordance with the connection mode of the cooling device and controlling a drying operation and moreover the moisture and the like can be removed without fail.